noun, plural can·vas·backs, (especially collectively) can·vas·back.
- a North American wild duck, Aythya valisineria, the male of which has a whitish back and a reddish-brown head and neck.
noun plural -backs or -back
- a North American diving duck, Aythyra valisineria, the male of which has a white body and reddish-brown head
also canvasback, 1785 as a type of North American duck. Earlier as an adjective for a type of garment made of expensive stuff in front and cheap canvas in the back (c.1600); from canvas (n.) + back (n.).